This invention relates to an improved arrow and in particular to a ring for a broadhead to direct the flow of air around a shaft to improve arrow flight stability.
Conventionally, for centuries arrows have been stabilized with fletching located at the rear of an arrow and aligned with the longitudinal axis of a shaft. An arrow so stabilized flies in a relatively straight path with the fletching aerodynamically bringing the arrow back to the line of flight whenever the arrow is disturbed from this idealized line. Recently attempts to change the aerodynamic flight characteristics of an arrow have been undertaken, but these have generally been limited to specific type airfoils. For instance see U.S. Pat. No. 4,182,513 which has an airfoil having a cross-sectional shape of a wing and located in the center portion of an arrow shaft. This airfoil is used to provide lift and extend the range of an arrow, but this airfoil does not streamline the airflow surrounding the shaft so that more air flows back entirely around the shaft to increase the airflow along all portions of the fletching.
In addition to the airfoil described above, rings have been used on arrowheads in the past to either increase the cutting capacity of the broadhead or to help hold the broadhead blades in position For instance see U.S. Pat. No. 2,888,264 as an example of a ring used to increase the cutting capacity in a wound and U.S Pat. No. 3,756,600 as an example of a ring holding blades in position. Not all archers want to increase the size of a wound however. Neither of the above listed patents illustrate rings that are used for the purpose of deflecting air toward the arrow shaft when the arrow is in flight. These patents also do not illustrate rings that break away from the blades upon target impact to remove the ring from any additional cutting action as the arrow enters the target.
An arrow's flight stability depends upon air flowing smoothly adjacent to the shaft and continuing smoothly along the fletching. A need exists for a broadhead guide ring which can be attached to a conventional broadhead to direct additional airflow inwardly and smoothly against the shaft to increase airflow over the fletching. This increased airflow is used to increase arrow stability. The broadhead guide ring should also be capable of breaking away from its flight position as a broadhead penetrates a target so that the blades enter the target in the conventional manner unimpeded by the guide ring.